Heretofore, α2δ ligands have been known as therapeutic drugs for neuropathic pain. Such α2δ ligands include, for example, gabapentine and pregabalin. The α2δ ligands including these compounds are useful in the treatment of epilepsy and neuropathic pain, etc. (e.g., Patent Literature 1). Other compounds are disclosed in, for example, Patent Literatures 2, 3, and 4.
The present applicant has also previously reported Patent Literatures 5 and 6 which disclose α2δ ligands and methods for producing the same.